?
Solved

AIX RamSan 2

Posted on 2014-01-29
2
Medium Priority
?
687 Views
Last Modified: 2014-02-07
this is 2nd part of the below Q

http://www.experts-exchange.com/OS/Unix/Q_28349015.html

IBM is talking about "ACA"
==================
Is that an sdd or aix setting (ACA)?

ramsan had it enabled by default.

what is your input here?
0
Comment
Question by:it-rex
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 68

Accepted Solution

by:
woolmilkporc earned 2000 total points
ID: 39819433
Do you mean "Auto Contingent Allegiance"?

That's a form of exception condition handling, exception recovery  and related message passing in the scsi protocol.

ACA is set when a "Check Condition" status occurs
ACA remains in effect until the initiator sends "Clear ACA"
During ACA only certain commands are allowed, marked by the ACA queue tag.

ACA (and CA, ECA which work a bit differently) are firmware driven.

AIX needs ACA being set to enable concurrent command processing. This is because ACA in a way disconnects the exception handling from command processing (a concurrent command can execute if allowed by the ACA queue tag before the recovery procedure for another command has completed).

Afaik on the Flash you can configure ACA on a per LUN basis, which specifies whether to handle check conditions on that LUN following the ACA method.
Again: For AIX, ACA is mandatory. It's not "settable", neither in AIX nor SDD.

On the DS8K, ACA is set by choosing the appropriate "hosttype" for the specific volgrp.

AIX had a problem with MPIO round robin and ACA, because it could happen that multiple "clear ACA" commands were sent, which could affect performance.
AIX 7.1 TL2 SP1 should have this problem fixed, though.


wmp
0
 
LVL 11

Author Closing Comment

by:it-rex
ID: 39842930
thanks
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In tuning file systems on the Solaris Operating System, changing some parameters of a file system usually destroys the data on it. For instance, changing the cache segment block size in the volume of a T3 requires that you delete the existing volu…
I have been running these systems for a few years now and I am just very happy with them.   I just wanted to share the manual that I have created for upgrades and other things.  Oooh yes! FreeBSD makes me happy (as a server), no maintenance and I al…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.
Suggested Courses
Course of the Month8 days, 9 hours left to enroll

764 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question